Method for fabricating an environmental barrier coating on a ceramic matrix composite

Patent metadata

Field	Value
Publication number	US-2024010574-A1
Application number	US-202318471373-A
Country	US
Kind code	A1
Filing date	Sep 21, 2023
Priority date	Aug 9, 2019
Publication date	Jan 11, 2024
Grant date	—

Abstract

A method of fabricating a coating includes providing a ceramic matrix composite that includes SiC fibers disposed in a SiC matrix, depositing a base slurry on the ceramic matrix composite, wherein the base slurry contains powders of a metal oxide, at least one of silicon carbide, silicon nitride, or free silicon, and barium-magnesium-aluminosilicate in a first carrier fluid, drying the deposited base slurry to produce a base green layer, depositing a transition slurry on the base green layer, wherein the transition slurry contains powders of a metal oxide, at least one of silicon carbide, silicon nitride, or free silicon, at least one of zirconium carbide, zirconium nitride, or zirconium oxide, and barium-magnesium-aluminosilicate in a second carrier fluid, drying the deposited transition slurry to produce a transition green layer, and forming a consolidated coating on the ceramic matrix composite by heating the base green layer and the at least one transition green layer to cause chemical reactions that convert the powders to metal-silicon-oxygen rich phase and metal-zirconium-oxygen rich phase.

First claim

What is claimed is:

1 . A method of fabricating a coating, the method comprising:
providing a ceramic matrix composite that includes SiC fibers disposed in a SiC matrix; depositing a base slurry on the ceramic matrix composite, wherein the base slurry contains, in parts by weight, 35-60 of a metal oxide powder, 5-20 of at least one of silicon carbide powder, silicon nitride powder, or free silicon powder, and 0.2-10 of barium-magnesium-aluminosilicate powder in a first carrier fluid; drying the deposited base slurry to produce a base green layer; depositing a transition slurry on the base green layer, wherein
the transition slurry contains, in parts by weight, 35-60 of a metal oxide powder, an amount X 1 of at least one of silicon carbide powder, silicon nitride powder, or free silicon powder, an amount X 2 of at least one of zirconium carbide powder, zirconium nitride powder, or zirconium oxide powder, and 0.2-10 of barium-magnesium-aluminosilicate powder in a second carrier fluid,
the total amount of X 1 +X 2 is 5-20, and
the amount X 1 is decreased and the amount of X 2 is increased through the deposition of the transition slurry;
drying the deposited transition slurry to produce a transition green layer; and forming a consolidated coating on the ceramic matrix composite by heating the base green layer and the transition green layer.

2 . The method as recited in claim 1 , wherein through the deposition of the transition slurry the amount X 1 is decreased to, and then held at, a non-zero amount, followed by decreasing the non-zero amount to zero.

3 . The method as recited in claim 1 , wherein the amount X 1 is decreased and the amount of X 2 is increased cooperatively such that through the deposition of the transition slurry X 1 +X 2 is constant.

4 . The method as recited in claim 1 , wherein the amount X 1 is linearly decreased and the amount of X 2 is linearly increased.

5 . The method as recited in claim 1 , wherein the metal oxide of the base slurry and the transition slurry is selected from the group consisting of HfO 2 , Y 2 O 3 , Yb 2 O 3 , Lu 2 O 3 , oxides of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and combinations thereof.

6 . The method as recited in claim 5 , further comprising applying a topcoat on the consolidated coating, the topcoat being selected from the group consisting of HfO 2 , Gd 2 Zr 2 O 7 , and combinations thereof.

7 . The method as recited in claim 1 , wherein the metal oxide of at least one of the base slurry or the transition slurry is HfO 2 .

8 . The method as recited in claim 1 , wherein the metal oxide of the base slurry and the transition slurry is HfO 2 .

9 . A gas turbine engine article comprising:
a ceramic matrix composite substrate that includes SiC fibers disposed in a SiC matrix; a coating disposed on, and in contact with, the ceramic matrix composite, the coating comprising, by volume percent,
5% to 20% of barium-magnesium-aluminosilicate, and
a remainder of a metal-silicon-oxygen rich phase and a metal-zirconium-oxygen rich phase dispersed through the barium-magnesium-aluminosilicate.

10 . The article as recited in claim 9 , wherein the metal-silicon-oxygen rich phase is HfSiO 4 and the metal-zirconium-oxygen rich phase is HfZrO 4 or HfO 2 and ZrO 2 .

11 . The article as recited in claim 9 , wherein the coating has a porosity, by volume, of 1% to 20%.

Assignees

• Rtx Corp

Inventors

• Smyth Imelda P
• Frith Sarah A

Classifications

• C04B41/5045 Primary

  Rare-earth oxides · CPC title

• C04B41/5307

  Removal of physically bonded water, e.g. drying of hardened concrete (E04B1/7007 takes precedence) · CPC title

• C04B41/0072

  Heat treatment · CPC title

• C04B41/4539

  as a emulsion, dispersion or suspension · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title